This prospective randomised study aims to investigate the heterologous immunological effects of DTP and seasonal influenza (Flu) vaccination in an elderly Tasmanian population and healthy adults. The study will assess whether prior or concurrent administration of DTP with seasonal Flu vaccination affects generalised inflammation / immune homeostasis and gene expression, with a particular focus of inflammation reactive cells. It will also analyse for effects of DTP on the induction of vaccine-specific immunity to seasonal influenza vaccination (antibodies and cellular). Volunteers will be randomised to one of three vaccine groups and serial blood samples taken for immunological assays for up to 30 weeks.